I was the dumpee, not the dumper, but this is how it went.
My best friend and first love of some two or three years became my sudden crush during our third year of knowing each other. I caught sudden feelings and, to say the least, it hit me like a truck. I concealed my feelings for them but they slowly began to slip out over a period of months.
During that time period, many of my insecurities began showing as I now reflect back on what happened. I was frankly unprepared; I had never loved someone than the way I loved them, nor did I really feel affectionate towards someone like I did towards them, and thus I was stuck in what seemed like an eternal honeymoon phase. They were always better than me, up on a pedestal, because they were just so perfect.
Fast forward to some days before Christmas, and they had been dating someone behind my back for like 4 months or more. I felt absolutely betrayed, gutted and at dismay. They knew I had a crush on them and I had asked them about shortly after (unknowingly to me at the time) they had begun dating this new person. I was backstabbed and I felt like I could never love anyone again after what happened to me. I tried to be their friend in the end, but for three days I couldn't do it, took a break from social media to rethink my life, and in the end, I decided to abandon ship and end my connection to them by myself.
Fast forward to now, I feel great about myself for doing what I did, and I'm proud that I did it because all that insecurity and despair has turned into confidence. I now frankly look back at these memories and laugh about it, gladly, because they don't hurt anymore, and I don't even remember half the details, to begin with!
Sooner or later, you'll get over it. For every person, it may take more or less time. It's just about how you work on yourself during this space that will matter, and what you should do is improve upon yourself by working out and so on of countless other things you could do to be ready for your next journey whatever it may be with the newfound experience.